• 제목/요약/키워드: logistic equation

검색결과 131건 처리시간 0.028초

적산온도에 의한 고로슬래그 미분말 혼입 콘크리트의 초기재령 압축강도의 예측 모델식 적용성 평가 (Evaluation on the Prediction Model for the Compressive Strength of Concrete mixing Blast Furnace Slag Powder at early-aged by Maturity Method)

  • 양현민;박원준;이한승
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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    • pp.251-252
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    • 2012
  • The exiting studies on the strength prediction by maturity method is mainly focused on concrete using OPC, meanwhile the study on the concrete mixing blast furnace slag powder (BFSP) is insufficient. The purpose of this study is to investigate the relationships between compressive strength and equivalent age by existing Maturity functions, i.e., Nurse-saul function Arrhenius function. This study also compared and examined the strength prediction of concrete mixing BGSP using ACI model and Logistic Curve prediction equation. Therefore, it is intended that fundamental data are presented for quality management and process management of concrete mixing BFSP.

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담배의 생장반응에 관한 수리해석적 연구 I. 전건물중의 생장곡선과 생장속도 (Studies on the Mathematical Analysis of Growth Kinetics in Tobacco (Nicotiana tabacum L. ) I. Growth Curve and Growth Velocity of Total Dry Weight.)

  • 김용암;변주섭
    • 한국연초학회지
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    • 제3권2호
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    • pp.109-114
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    • 1981
  • This experiment was conducted with three varieties (Hicks, Burley 21, Sohyang) and cropping systems (Improved mulching, Mulching, Non mulching) of NC 2326 to analyze growth kinetics by means of growth function involving its velocity and accelerated velocity. The basic growth data were obtained by harvest method at interval of ten days from transplanting to hundred days and analyzed by , regression equation, determinant of matrix, and differentiation. The plot of total dry weight of leaves, stalk and roots per a plant vs. time forms a sigmoid curve and its function fitted logistic satisfactorily. Tobacco plant grows at an accelerated velocity. And growth velocity, symmetric about an inflection point, is proportional to biomass attained and to the difference between biomass attained and the maximum, and to the decrease according to the biomass. Of varieties and cropping systems, the most maximum velocity was 9.58g per day per plant in mulching cultivation of NC 2326 and maximum accelerated velocity was 264mg per $day^2$ per plant in Burley 21.

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적산온도에 의한 콘크리트 압축강도 추정모델의 적용성 검토 (Application on the Prediction Model of the Compressive Strength of Concrete by Maturity Method)

  • 길배수;권영진;남재현;김무한
    • 한국구조물진단유지관리공학회 논문집
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    • 제3권2호
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    • pp.177-183
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    • 1999
  • The major object of this study is to investigate experimentally the experimental equation by the non-destructive testing methods of ultrasonic pulse velocity, rebound number, combined method of ultrasonic pulse velocity and rebound number, maturity which are applicable to the evaluation of compressive strength of concrete at early ages. Also test result of mix are statistically analyzed to infer the correlation coefficient between the maturity and the compressive strength of concrete. The results show good application of Logistic curve for estimating strength development under various curing temperature. The relation between ultrasonic pulse velocity, rebound number, combined method of ultrasonic pulse velocity and rebound number and compressive strength of concrete have low correlation coefficient, but maturity method show good correlation coefficient.

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민들조개 (Gomphina melanaegis) 형망의 갈퀴에 의한 어획선택성 (Tooth selectivity on venus clam (Gomphina melanaegis) dredge)

  • 박해훈;김승환
    • 수산해양기술연구
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    • 제36권4호
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    • pp.267-273
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    • 2000
  • 민들조개 형망의 갈퀴에 의해 어획될 확률을 조개크기와 갈퀴간격 사이의 관계로부터 구했다. 이때 기존의 방법에서는 각장만을 이용했는데 여기서는 각장 이외에 각고(또는 각폭)에 의한 효과를 추가시켜 어획될 확률을 구하고 로지스틱 어획선택성 곡선에 적합시켰으며, 그식은 다음과 같았다. P=(equation omitted)$.$민들조개의 경우 생물학적 최소형은 각장이 25mm인 것으로 알려져 있으며, 이 최소성숙각장에 대해 50% 어획될 갈퀴간격을 구하면 16.2mm이다. 따라서, 민들조개 형망의 적정 갈퀴간격은 기존에 사용하고 있는 12mm를 16mm로 늘리는 것이 자원보호상 바람직하며, 이것은 예망작업시 모래 속을 끄는 갈퀴의 갯수도 상대적으로 적어지므로 어구저항이 감소되어 연료가 절약되며, 선상에서는 작은 조개를 체를 이용하여 거르는 인력작업도 줄일 것으로 여겨진다.

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신규면허간호사 공급량 증가가 의료기관 간호사 확보수준에 미친 영향과 정책적 함의 (Impact of Increased Supply of Newly Licensed Nurses on Hospital Nurse Staffing and Policy Implications)

  • 김윤미;유선주;김진현
    • 대한간호학회지
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    • 제47권6호
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    • pp.828-841
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    • 2017
  • Purpose: This study aimed to analyze the impact of increasing the supply of newly licensed nurses on improving the hospital nurse staffing grades for the period of 2009~2014. Methods: Using public administrative data, we analyzed the effect of newly licensed nurses on staffing in 1,594 hospitals using Generalized Estimating Equation (GEE) ordered logistic regression, and of supply variation on improving staffing grades in 1,042 hospitals using GEE logistic regression. Results: An increase of one newly licensed nurse per 100 beds in general units had significantly lower odds of improving staffing grades (grades 6~0 vs. 7) (odds ratio=0.95, p=.005). The supply of newly licensed nurses increased by 32% from 2009 to 2014, and proportion of hospitals whose staffing grade had improved, not changed, and worsened was 19.1%, 70.1%, and 10.8% respectively. Compared to 2009, the supply variation of newly licensed nurses in 2014 was not significantly related to the increased odds of improving staffing grades in the region (OR=1.02, p=.870). Conclusion: To achieve a balance in the regional supply and demand for hospital nurses, compliance with nurse staffing legislation and revisions in the nursing fee differentiation policy are needed. Rather than relying on increasing nurse supply, retention policies for new graduate nurses are required to build and sustain competent nurse workforce in the future.

Circularity Index on Contrast-Enhanced Computed Tomography Helps Distinguish Fat-Poor Angiomyolipoma from Renal Cell Carcinoma: Retrospective Analyses of Histologically Proven 257 Small Renal Tumors Less Than 4 cm

  • Hye Seon Kang;Jung Jae Park
    • Korean Journal of Radiology
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    • 제22권5호
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    • pp.735-741
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    • 2021
  • Objective: To evaluate circularity as a quantitative shape factor of small renal tumor on computed tomography (CT) in differentiating fat-poor angiomyolipoma (AML) from renal cell carcinoma (RCC). Materials and Methods: In 257 consecutive patients, 257 pathologically confirmed renal tumors (either AML or RCC less than 4 cm), which did not include visible fat on unenhanced CT, were retrospectively evaluated. A radiologist drew the tumor margin to measure the perimeter and area in all the contrast-enhanced axial CT images. In each image, a quantitative shape factor, circularity, was calculated using the following equation: 4 x π x (area ÷ perimeter2). The median circularity (circularity index) was adopted as a representative value in each tumor. The circularity index was compared between fat-poor AML and RCC, and the receiver operating characteristic (ROC) curve analysis was performed. Univariable and multivariable binary logistic regression analysis was performed to determine the independent predictor of fat-poor AML. Results: Of the 257 tumors, 26 were AMLs and 231 were RCCs (184 clear cell RCCs, 25 papillary RCCs, and 22 chromophobe RCCs). The mean circularity index of AML was significantly lower than that of RCC (0.86 ± 0.04 vs. 0.93 ± 0.02, p < 0.001). The mean circularity index was not different between the subtypes of RCCs (0.93 ± 0.02, 0.92 ± 0.02, and 0.92 ± 0.02 for clear cell, papillary, and chromophobe RCCs, respectively, p = 0.210). The area under the ROC curve of circularity index was 0.924 for differentiating fat-poor AML from RCC. The sensitivity and specificity were 88.5% and 90.9%, respectively (cut-off, 0.90). Lower circularity index (≤ 0.9) was an independent predictor (odds ratio, 41.0; p < 0.001) for predicting fat-poor AML on multivariable logistic regression analysis. Conclusion: Circularity is a useful quantitative shape factor of small renal tumor for differentiating fat-poor AML from RCC.

동북아 물류거점화를 위한 연안해운 경쟁력 제고방안에 관한 연구 (A Study on the Competitiveness Improvement of Coastal Shipping for Northeast Asia Logistics-Hub)

  • 이윤재;안기명;김현덕;김광희
    • 한국항해항만학회지
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    • 제29권6호
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    • pp.501-508
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    • 2005
  • 연안해운과 관련한 최근 환경 변화는 남북해운합의서 발효에 따른 남북물류의 증대 가능성과 환황해권, 환동해권의 동북아 연안 부상 등을 언급할 수 있다. 그러니, 연안해운에 대한 국가 정책의 소외는 우리나라라 물류거점화 되는데 많은 문세점을 노출하고 있다. 이러한 문제점을 해소하고 외항과 연안간 균형발전을 도모하여 우리나라가 동북아 물류거점화 할 수 있는 방안을 크게 연계수송체제의 강화. 연안해운의 체질강화 및 정부의 체계적인 지원정책으로 구분, 제시하는 것이 본 연구의 목적이다. 연구결과에 의하면, 첫째로, 연계수송체계를 강화하기 위해 거점항만내에 연안피더 전용선석의 구축으로 연안피더운송의 연계성 강화가 필요하며 둘째로, 언안부두에 화주즐 유인할 수 있는 공동장치장 및 하역설비를 대폭 보강하여 일괄 서비스체제의 확립, 노후 비경계선의 Ro-Ro 선 혹은 고속컨테이너선으로의 대체. 화물선에 대한 면세유 공급과 각종 세제의 실질적인 혜댁부여로 환경 친화적이며 균형있는 외항-연안 물류사슬체계(Logistics Chain System)를 갖추는 것이 필요한 것으로 나타나고 있다.

파에서 정식초기 파총채벌레의 경제적피해수준 설정 (Economic Injury Level of Thrips tabaci (Thysanoptera: Thripidae) on Welsh onions (Allium fistulosum L. var) in the Early Transplanting Stage)

  • 강택준;조명래;김형환;전흥용;김동순
    • 한국응용곤충학회지
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    • 제50권4호
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    • pp.289-293
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    • 2011
  • 파정식 초기 파총채벌레의 경제적피해허용수준을 설정하기 위하여 온실에서 파총채벌레 접종기간에 따른 파의 생육, 피해 및 수량을 조사하였다. 파 정식초기에는 파총채벌레 접종기간(즉 가해정도)에 따른 수량감소율은 5일, 10일, 15일, 20일 접종기간에서 각각 17.0%, 53.3%, 38.4%, 80.8%로 증가하였다. 파총채벌레 발생정도와 파 수량감소 관계를 구명하기 위하여 파총채벌레 누적밀도일(Cumulative Insect Days, CID)과 수량 감수량(%) 간 회귀분석을 실시한 결과 비선형식인 logistic 모형에 잘 적용되었다. 이 식으로부터 경험적인 수익한계(Gain Threshold) 5%와 통상적 상품화율(93%)를 감안한 수량 감소율 12% 수준에서 파총채벌레 경제적피해허용수준은 30 CID로 추정되었다. 또한 요방제밀도는 경제적피해수준의 80%가 되는 24 CID로 추정되었다. 본 결과는 더 개선된 모형이 개발될 때까지 파 생육초기 파총채벌레 관리에 유용하게 활용될 수 있을 것으로 판단되었다. 또한 파 노지포장에서 생육후기(정식 후 120일 접종) 파총채벌레 피해가 파 수량에 미치는 영향을 검토한 결과, 파 생육후기에는 낮은 밀도에서 오히려 수량이 증가하였고, 그 후 밀도가 더 증가함에 따라 수량이 감소하는 등 전형적인 보상적 반응(over-compensatory response)을 보였다.

지하매설물 속성정보를 활용한 지반함몰 영향인자 분석 (Analysis of Ground Subsidence Influencing Factors Using Underground Facility Property Information)

  • 강재모;이성열;김진영;공명식
    • 한국지반환경공학회 논문집
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    • 제25권1호
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    • pp.5-11
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    • 2024
  • 지반함몰은 인구 밀집도가 높은 도심지에서 주로 발생함으로, 발생 원인을 명확히 파악하여 사전에 대비할 필요가 있다. 지반함몰의 주요 발생원인은 지하매설관의 손상으로 인한 지반 내 공동 생성으로 보고되어 있으나, 지반함몰 발생을 예측하여 대비하기 위한 지하매설관의 속성정보 및 영향인자가 올바르게 구축되어 있지 않은 실정이다. 따라서 본 연구에서는 지하매설물 속성정보 중 지반함몰 발생과 유의미한 상관성을 나타내는 인자를 선정하고, 로지스틱 회귀분석을 통해 회귀식을 제안하였다. 이를 위해, 대상지역의 지하매설물 및 지반함몰 이력정보의 데이터를 수집하였고, 대상지역을 QGIS를 활용하여 100m×100m 크기의 Gird로 구분하였다. Gird 내부에 포함되어 있는 지하매설물 속성정보와 지반함몰 이력정보를 추출하여 전처리를 수행하고 데이터셋을 구축하여 상관분석을 수행하였다. 그 결과, 하수관과 통신관의 매설년도와 통신관, 열배관, 가스관의 평균심도를 제외한 인자가 지반함몰과 유의미한 상관성을 보이는 것으로 나타났다. 또한, 로지스틱 회귀분석을 통해 대상지역의 지반함몰 발생 여부 회귀식을 제안하였다.

Growth curve estimates for wither height, hip height, and body length of Hanwoo steers (Bos taurus coreanae)

  • Park, Hu-Rak;Eum, Seung-Hoon;Roh, Seung-Hee;Sun, Du-Won;Seo, Jakyeom;Cho, Seong-Keun;Lee, Jung-Gyu;Kim, Byeong-Woo
    • 농업과학연구
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    • 제44권3호
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    • pp.384-391
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    • 2017
  • Growth curves in Hanwoo steers were estimated by Gompertz, Von Bertalanffy, Logistic, and Brody nonlinear models using growth data collected by the Hanwoo Improvement Center from a total of 6,973 Hanwoo (Bos taurus coreanae) steers 6 to 24 months old that were born between 1996 and 2015. The data included three parameters: A, mature size of body measurement; b, growth ratio; and, k, intrinsic growth rate. Nonlinear regression equations for wither height according to Gompertz, Von Bertalanffy, Logistic, and Brody models were $Y_t=144.7e^{-0.5869e^{-0.00301t}}$, $Y_t=145.3(1-0.1816e^{-0.00284t})^3$, $Y_t=143.1(1+0.7356e^{-0.00352t})^{-1}$, and $Y_t=146.8(1+0.4700e^{-0.00249t})^1$, respectively, while those for hip height were $Y_t=144.5e^{-0.5549e^{-0.00312t}}$, $Y_t=145.0(1-0.1724e^{-0.00295t})^3$, $Y_t=143.1(1+0.6863e^{-0.00360t})^{-1}$, and $Y_t=146.2(1+0.4501e^{-0.00263t})^1$, respectively. Equations for body length $Y_t=174.1e^{-0.8342e^{-0.00289t}}$, $Y_t=175.8(1-0.2500e^{-0.00265t})^3$, $Y_t=170.0(1+1.1548e^{-0.00363t})^{-1}$, and $Y_t=180.3(1+0.6077e^{-0.00215t})^1$, respectively, for the same models. Among the four models, the Brody model resulted in the lowest mean square error, with mean square errors of 31.79, 30.57, and 42.13, respectively, for wither height, hip height, and body length. Also, an estimated birth wither height, birth hip height, and birth body length (77.98, 80.57, and 70.97 cm, respectively) were lower in the Brody model than in other models. An inflection point was not observed during the growth phase of Hanwoo steer according to the growth curves calculated using Gompertz, Von Bertalanffy, and Logistic models. Based on the results, we concluded that the regression equation using the Brody model was the most appropriate among the four growth models. To obtain more accurate parameters, however, using data from a wider production period (from birth to shipping) would be required, and the development of a suitable model for body conformation traits would be needed.